Micro FA Mycology/Parasitology p151 -161 Flashcards by Sahaja Parsa

Systemic mycosis from
Mississippi and Ohio River Valleys

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Mycoses from Eastern and Central US, Great Lakes

Usually NC/SC - gen E of Mississippi River

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Systemic mycoses from Southwestern US, California

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Systemic mycosis from Latin America

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Sx of Histoplasmosis

Palatal/tongue ulcers, splenomegaly, pancytopenia

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Patho signs of Histoplasmosis

Macrophage filled with Histoplasma (smaller than RBC

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Where is histoplasma found?

bird (starlings) or bat droppings

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Dx of Histoplasmosis

Diagnosis via urine/ serum antigen

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Patho features of blastomycosis

Broad-based budding of Blastomyces (same size as RBC)

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skin lesions of blastomycosis look like what neoplasm?

looks like SCC

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Sx of blastomycosis

Inflammatory lung disease, can disseminate to skin/ bone

granulomatous nodules

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Patho features of Coccidiodomycosis

Spherule (much larger than RBC) filled with endospores of Coccidioides

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Sx of Coccidioidomycosis

Disseminates to skin/ bone Erythema nodosum (desert bumps) or multiforme Arthralgias (desert rheumatism) Can cause meningitis

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Patho features of Paracoccidioidomycosis

Budding yeast of Paracoccidioides with “captain’s wheel” formation (much larger than RBC

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3 dermatophytes - which infects what

Trichophyton - 3 skin, hair, and nails

Epidermophyton - skin and nails

(phyton - “fightin” tooth & nail)

Microsporum - skin and hair

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Tinea corporis - acquired from?

contact with infected pets or farm animals

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causative agent of tinea versicolor

Malassezia furfur

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What leads to the different pigmentation pattern of tinea versacolor

Degradation of lipids produces acids that inhibit tyrosinase (involved in melanin synthesis) –> hypopigmentation
hyperpigmentation and/or pink patches can also occur due to inflammatory response.

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Which mycoses is described morphologically as round yeast clusters with short curved hyphae?

Malassezia (“spaghetti & meatballs”)

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Dx with Wood’s lamp or KOH skin scraping

Tinea

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form pseudohyphae and budding yeasts at 20^oC, germ tubes at 37^oC

Candida albicans

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Candida is NF of where?

mucous mem

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septate hyphae that branch at 45^o

Aspergillus

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non dimorphic heavily encapsulated yeast

Cryptococcus

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What does Candida cause in the immunocomromised?

oral and esophageal thrush

Candida vulvovaginitis is seen in what patient pop?

Diabetes pt (Fungi love sugar) pt on inc antibiotic use

IV drug users can get what manifestation of candida?

endocarditis

Chronic mucocutaneous candidiasis seen in what pts?

Anyone with a Th1 defect DB

Can form a ball like structure in pre-existing lung cavities, like after a TB infection

Aspergillus - aspergilloma (fungus ball)

Some species of Aspergillus produce _______ (associated with what neoplasm).

Some species of Aspergillus produce Aflatoxins (associated with hepatocellular carcinoma).

Tx of Aspergillus

voriconazole or echinocandins (2nd-line).

Patients with asthma or cystic fibrosis will have what response to Aspergillus

Allergic bronchopulmonary aspergillosis (ABPA)—**hypersensitivity response** to Aspergillus growing in _lung mucus_. Associated with asthma and cystic fibrosis; may cause **bronchiectasis and eosinophilia.**

Most sensitive/specific test for Cryptococcus

Latex agglutination test detects polysaccharide capsular antigen and is more sensitive and specific.

found in soil, pigeon droppings

Cryptococcus

What does Cryptococcus cause?

Acquired through inhalation with hematogenous dissemination to meninges. therefore, leads to Cyptococcal pneumonia (cryptococcosis) and meningitis, encephalitis

At what CD count do you treat Candida, Histoplasma, Pneumocystis, Cryptococcus and Aspergillus

\<500/mm3 * Candida albican oral thrush \<200/mm3 * Histoplasma * Pneumocystis \<100/mm3 * Candida esophagitis * Aspergillus * Cryptococcus meningitis

irregular ribbon like broad non septate hyphae that branch at wide angles

Mucor/Rhizopus/Absidia

Mucormycosis seen in which pt pop?

Diabetes (ketoacidotic) neutropenic pt (leukemia)

Pathogenesis of Mucor, Sx/

Inhalation of spores --\> fungi proliferate in blood vessel walls, penetrate cribriform plate, and enter brain. Rhinocerebral, frontal lobe abscess; cavernous sinus thrombosis. Headache, facial pain, black necrotic eschar on face; may have cranial nerve involvement.

diffuse interstitial pneumonia caused by fungi in immune compromised pt?

Pneumocystis

disc shaped yeast seen on methenamine silver stain of lung tissue

Pneumocystis - honey comb like - dark colonies on a green background

Dx of Pneumocystis - why?

Diagnosed by bronchoalveolar lavage or lung biopsy Pneumocystis - attaches to and kills type I pneumocytes --\> leads to prolifer'n of type II --\> alveoli fill with a dense exudate, can't cough it up. Have to go in for it

Tx of Pneumocystis

TMP-SMX

Dimorphic, cigar-shaped budding yeast that grows in branching hyphae with rosettes of conidia

Sporothrix Schenckii

Typical presentation of Sporothrix

When spores are traumatically introduced into the skin, typically by a thorn (“rose gardener’s disease”), causes local pustule or ulcer with nodules along draining lymphatics (ascending lymphangitis

Immunocompromised pt with Sporothrix - presentation, common pt pop?

Disseminated disease possible in immunocompromised host. -- pulm sprotrichosis Seen in homeless, alcoholic pt inhaling infection form

Tx of sporthrix

itraconazole, KI (cutaneous)

bloating flatulence foul smelling diarrhea + camping/hiking

Giardia

bloody diarrhea + travel to tropics/mexico

Entamoeba histolytica

flask shaped ulcers on colon biopsy

entamoeba histolytica

What causes chronic watery diarrhea in an AIDS pt ? When do we Prophylactically tx?

Cryptosporidium \<50 (\<100 CD4 count)

multiple ring enhancing lesions in CNS

brain abscesses of Toxoplasma - but look for AIDS Also Glioblastoma

Congential Toxoplasmosis

chorioretinitis (neonatal blindness) hydrocephalus intracranial calcifications

Tx of Toxoplasma - what CD # do we prophylax?

Sulfadiazine, pyrimethamine CD# \<100

Primary sources of Toxoplasma

1. undercooked pork 2. Cat feces

In immunocompetent pt, how does Toxoplasma look?

Like mono - but heterophile Ab test (-)

Diving in warm water - what organism?

Naegleria fowleri

How does Naegleria lead to meningoencephalitis?

Crawling up the cribriform plate

why is there a recurring fever with Trypansoma?

antigenic variation Covered in variant surface glycoproteins Ab fight it ---\> fever --\> new VSG

Transmission of Trypansoma from ?

Tsetse fly

Sx of Typansoma

African sleeping sickness enlarged l.n., recurring fever, large red chancre at bite site --\> somnolence --\> coma

Diff b/w P. vivax/ovale and P malariae fever cycle

Vivax and ovale - 48 hr fever cycle malariae - 72 hr fever cycle

What is p. falciparum fever cycle? why is it diff?

No regular fever spikes - Fever spikes due to RBC lysis, but unlike vivax/ovale/malariae the lysis of RBC is not synchonized, but occur individually - keeps the fever up

dormant form of p vivax/ovale - lives where? How do we treat this form?

Liver - hypnozoite Add Primaquine for radical cure

P falciparum infects what? leads to?

parasite infected RBC will occlude capillaries in brain, kidneys, lung ---\> tissue hypoxia, lactic acidosis, hypoglycemia

Transmission of Plasmodium

Anopheles mosquito

Vector for Babesia? Also transmits which other organisms?

Ixodes tick same as Borrelia burgdorferi (Lyme) & Anaplasma (Ehrlichia is Lone star tick Amblyomma)

Sx of Babesia

fever and hemolytic anemia

What can predispose one to more severe form of Babesia?

asplenia (thru op or practically)

Which people have natural immunity vs Plasmodium?

HbS heterozygote protected from p falciparum Duffy blood group neg - from p. vivax Thalassemia/Ab Normal Hgb - from plasmodium

unilateral periorbital swelling

Chagas disease - T cruzi

What cell type does T cruzi infect --\> what are the consequences?

cardiac musc and smooth m. --\> dilated cardiomyopathy, megacolon, mega esophagus

Vector for T Cruzi?

Reduviid bug (kissing bug) Triatomine insect

vector of Leishmania?

sandfly

foul smelling, greenish discharge from vagina

Trichomonas vaginalis

Which nematodes do you get from ingesting them?

Enterobius Ascaris Toxocara Trichinella Trichuris

Which nematodes come thru the skin?

Strongyloides, Ancyclostoma, Necator

Nematode transmitted thru bite

Loa Loa, Onchocerca volvulus Wulchereria bancrofti

Causes anal pruritus

Enterobius vermicularis pin worm

May cause obstruction at ileocecal valve, biliary obstruction, intestinal perforation, migrates from nose/mouth

Ascaris lumbricoides (giant roundworm)

young child, can see larvae in sputum

Ascaris lumbricoides

causes microcytic hypochromic anemia

Ancylostoma , Necator AN iron sucker

From wild game

Trichinella spiralis

fever, vomiting, nausea, periorbital edema, myalgia, splinter hemorrhages, eosinophils

Trichinella spiralis

loose stools, anemia, rectal prolapse in children

Trichuris trichiura (whipworm) TrichuRIS - Rectum is Slipped

Micro FA Mycology/Parasitology p151 -161 Flashcards

(85 cards)